Spine alignment system

ABSTRACT

A spine alignment system is disclosed. The spine alignment system includes a pedicle screw having a longitudinal axis, the pedicle screw having a screw head. The screw head includes a slot having a longitudinal axis that is substantially perpendicular to the longitudinal axis of the pedicle screw. An extension shaft is secured to the pedicle screw, such that a longitudinal axis of the extension shaft is substantially coaxial with the longitudinal axis of the pedicle screw. The spine alignment system also includes a cap having a slot that forms a substantially cylindrical passage with the slot of the pedicle screw head. The substantially cylindrical passage is configured to receive an alignment rod such that alignment of the spine occurs as the rod is translated along the extension shaft to the pedicle screw.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/987,701, filed Aug. 7, 2020, which is a continuation of U.S. patentapplication Ser. No. 16/049,244 (U.S. Pat. No. 10,736,668), filed Jul.30, 2018, which is a continuation of U.S. patent application Ser. No.14/964,490 (U.S. Pat. No. 10,034,690), filed Dec. 9, 2015, which claimsthe benefit of U.S. Provisional Application No. 62/089,725, filed Dec.9, 2014, and U.S. Provisional Application No. 62/180,870, filed Jun. 17,2015, which are hereby incorporated by reference herein in theirentirety, including but not limited to those portions that specificallyappear hereinafter, the incorporation by reference being made with thefollowing exception: in the event that any portion of theabove-referenced applications are inconsistent with this application,this application supersedes said above-referenced applications.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

BACKGROUND

The Field of the Present Disclosure.

The present disclosure relates generally to spinal alignment andstabilization devices.

DESCRIPTION OF RELATED ART

Curvature and deformities of the spine impact many people and can haveserious, and even life-threatening, health consequences. Beneficially,curvature and deformities of the spine can often be treated variousprocedures, including spinal fusion surgery, which permanently connectstwo or more vertebrae in a spine, eliminating motion between them. Thistype of spinal fusion can improve stability of the spine while alsocorrecting deformities, reducing pain and improving the life qualify ofa patient. Spinal fusion often involves placing a bone graft in thespace between two spinal vertebrae.

A surgeon may use plates, screws or rods to hold the vertebrae and graftin place to promote healing after spinal fusion. Once the bone graftheals, the vertebrae are permanently connected.

Bony anchors or screws are commonly used to secure the vertebrae to alongitudinal alignment rod. These may connect multiple level anchors.Typically, two alignment rods are utilized between each level, one oneach side of the spinous process. However, conventional spine alignmentdevices are characterized by being overly complex, needing numerousindividual parts and tools for assembly and installation.

Conventional alignment devices are thus characterized by severaldisadvantages that are addressed by the present disclosure. The presentdisclosure minimizes, and in some aspects eliminates, theabove-mentioned failures, and other problems, by utilizing the methodsand structural features described herein.

The features and advantages of the present disclosure will be set forthin the description which follows, and in part will be apparent from thedescription, or may be learned by the practice of the present disclosurewithout undue experimentation. The features and advantages of thepresent disclosure may be realized and obtained by means of theinstruments and combinations particularly pointed out in the appendedclaims. An understanding of the present disclosure will provide anappreciation of the unique and beneficial combination of the engineeringsciences and the medical sciences which result in heretofore unavailableadvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the disclosure will become apparent froma consideration of the subsequent detailed description presented inconnection with the accompanying drawings in which:

FIG. 1 is an exploded perspective view of a mono-axial embodiment of thepresent disclosure;

FIG. 2 is an exploded front view of the embodiment of FIG. 1 ;

FIG. 3 is an exploded side view of the embodiment of FIG. 1 ;

FIG. 4 is a cross-sectional view of a mono-axial pedicle screw of theembodiment of FIG. 1 ;

FIG. 5 is a top view of a cap of the embodiment of FIG. 1 ;

FIG. 5 a is a side view of the cap of the embodiment of FIG. 1 ;

FIG. 6 is an assembled perspective view of the embodiment of FIG. 1 ;

FIG. 7 is an assembled front view of the embodiment of FIG. 1 ;

FIG. 8 is an assembled side view of the embodiment of FIG. 1 ;

FIG. 9 is an assembled, cross-sectional side view of the embodiment ofFIG. 1 ;

FIG. 10 is an assembled perspective view of the embodiment of FIG. 1 ,as illustrated in FIG. 9 , shown without an alignment rod;

FIG. 11 is an assembled side view of the embodiment of FIG. 1 without analignment rod;

FIG. 12 is a perspective view of an inner rod of the embodiment of FIG.1 ;

FIG. 13 is an assembled side view of the embodiment of FIG. 1 without anextension shaft;

FIG. 14 is an assembled, cross-sectional side view of the embodiment ofFIG. 1 without an extension shaft;

FIG. 15 is an exploded side view of a poly-axial embodiment of thepresent disclosure;

FIG. 16 is an exploded cross-sectional view of the embodiment of FIG. 15;

FIG. 17 is an assembled cross-sectional view of the embodiment of FIG.15 ;

FIG. 18 is an assembled front view of the embodiment of FIG. 15 ;

FIG. 19 is an assembled perspective view of the embodiment of FIG. 15 ;

FIG. 20 is an assembled side view of the embodiment of FIG. 15 ;

FIG. 21 is an exploded perspective view of the embodiment of FIG. 15 ,including a cap and an alignment rod;

FIG. 22 is an exploded front view of the embodiment of FIG. 21 and asillustrated in FIG. 21 ;

FIG. 23 is an exploded side view of the embodiment of FIG. 21 ;

FIG. 24 is an assembled, perspective view of the embodiment of FIG. 21 ;

FIG. 25 is an assembled cross-sectional view of the embodiment of FIG.21 ;

FIG. 26 is an assembled perspective view of the embodiment of FIG. 21without an extension shaft;

FIG. 27 is an embodiment of a contoured alignment rod;

FIG. 28 is top view of an embodiment of the disclosed spine alignmentsystem;

FIG. 29 is top view of the embodiment of FIG. 28 before alignment rodsare secured;

FIG. 30 is an exploded view of the embodiment of FIG. 28 ;

FIG. 31 is a partially assembled view of the embodiment of FIG. 28 ;

FIG. 32 is a further assembled view of view of the embodiment of FIG. 28; and,

FIG. 33 is side view of a fully assembled embodiment of FIG. 28 .

DETAILED DESCRIPTION

For the purposes of promoting an understanding of the principles inaccordance with the disclosure, reference will now be made to theembodiments illustrated in the drawings and specific language will beused to describe the same. It will nevertheless be understood that nolimitation of the scope of the disclosure is thereby intended. Anyalterations and further modifications of the inventive featuresillustrated herein, and any additional applications of the principles ofthe disclosure as illustrated herein, which would normally occur to oneskilled in the relevant art and having possession of this disclosure,are to be considered within the scope of the disclosure claimed.

It must be noted that, as used in this specification and the appendedclaims, the singular forms “a,” “an,” and “the” include plural referentsunless the context clearly dictates otherwise.

In describing and claiming the present disclosure, the followingterminology will be used in accordance with the definitions set outbelow.

As used herein, the terms “comprising,” “including,” “containing,”“characterized by,” and grammatical equivalents thereof are inclusive oropen-ended terms that do not exclude additional, unrecited elements ormethod steps.

Applicant has discovered a novel apparatus and method for aligning,stabilizing and securing adjacent spinal vertebrae using a spinealignment system utilizing side loading and incremental reduction ofadjacent spinal vertebrae to an alignment rod. This means that analignment rod can be captured into a side of the a corresponding pediclescrew, as opposed to capturing the alignment rod on top of the pediclescrew.

FIGS. 1-14 illustrate an spine alignment system 100 according to a firstembodiment of the current disclosure. The spine alignment system 100includes a mono-axial, or fixed axis, pedicle screw 102. The pediclescrew 102 includes a threaded shaft 104 which facilitates insertion andfixation into the bony pedicle of a vertebral body. The threaded shaft104 may have a fixed or tapered diameter, with single or multiple startthreads which may be spaced between 1 mm and 3 mm apart, for example.

The pedicle screw 102 includes a head 106 having a generally conicalshape. The head 106 includes an approximately C-shaped cut-out portion108, or slot, located substantially on a side of the head 106. The slot108 includes a longitudinal axis that is substantially perpendicular tothe longitudinal axis of the pedicle screw 102. The conical shape of thehead 106 converts to a cylindrical shape above the slot 108, resultingin a cylindrical portion 110. The cylindrical portion 110 includes anexterior thread configured to receive a locking nut 112.

The cylindrical portion 110 of the head 106 can also include a key slot114 configured to receive a key 116 of an extension shaft 118. Theextension shaft 118 includes external threads that are formed to matchthe threads on the cylindrical portion 110 of the head 106. When the key116 of the extension shaft 118 is received into the key slot 114, thethreads of the extension shaft 118 will perfectly match the threads ofthe cylindrical portion 110 of the head 106, such that the locking nut112 can threadedly engage the extension shaft 118 and the cylindricalportion 110 of the head 106.

An inner rod 120 is substantially cylindrical in shape and is configuredto be received within a longitudinal through-hole 122 in the extensionrod 118, as shown in FIG. 10 . The inner rod 120 includes a threadeddistal end 124 and a stepped portion 126 near the proximal portion ofthe inner rod 120. The threaded distal end 124 is configured tothreadedly engage a threaded bore 128 within the head 106 of the pediclescrew 102. The stepped portion 126 of the inner rod 120 is configured toabut against the proximal end of the extension shaft 118, which therebysecures the extension shaft 118 to the head 106 of the pedicle screw102.

In another embodiment, the extension shaft 118 can be integrated withthe head 106 of the pedicle crew 102 with a fracture groove cut into adistal end of the extension shaft 118, which can enable the extensionshaft 118 to break-away from the head 106 of the pedicle screw 102 afterinstallation of the spine alignment system 100.

Once the inner rod 120 has secured the extension shaft 118 to thepedicle screw 102, a surgeon or user can insert or screw the pediclescrew 102 into the bony pedicle of a vertebra. The inner rod 120includes a head 130, which can be configured to receive a drillattachment, or manual driver attachment, which can help facilitate thedriving or screwing of the pedicle screw 102 into the bony pedicle of avertebra.

The extension shaft 118 is configured to receive a cap 132. The cap 132includes an oblong through-hole 134 that includes a substantially flatside surface 136 that is configured to lie flat against a flat sidesurface 138 of the extension shaft 118. The extension shaft 118 includesa pair of opposing flat side surfaces 138, one of the pair of flatsurfaces 138 faces the same direction as the slot 108 of the pediclescrew 102. These flat side surfaces 138 serve as a guide for the cap 132after capturing an alignment rod 140 and translating down the length ofthe extension shaft 118. The alignment rod 140 is captured by the cap132 within an approximately C-shaped cutout 142, or slot, that is formedand dimensioned to substantially the same diameter as the alignment rod140.

One of the pair of flat surfaces 138 engages the alignment rod 140,pressing against the alignment rod 140 while the alignment rod isengaged within the slot 142, helping secure the alignment rod 140 inplace during axial translation of the cap 132. The opposing flat surface138 of the extension shaft will engage the flat surface 136 within thecap 132, creating substantially co-planar contact between the twosurfaces resulting a rotationally locked engagement, helping to preventunwanted rotation of the cap 132 during axial translation down theextension shaft 118.

The cap 132 may also be configured to form the slot 142 with an arclength angle of θ, where θ may be greater than 180 degrees. The slot 142having an arc length angle of greater that 180 degrees enables the slotto receive the alignment rod 140 with a snap-fit engagement. The smallflexibility of the cap material allows the slot 142 to deform enough toallow the alignment rod to be received therein, then retain thealignment rod 140 within the slot 140. Alternative cap embodiments mayalso include a slot having an arc length angle that is 180 degree, orless than 180 degrees.

During assembly and use, a surgeon or user will insert and secure thepedicle screw 102, with the adjoined extension shaft 118, to the bonypedicle of a desired vertebra. Once the pedicle screw 102 is secured,the surgeon or user can then place the cap 132 onto the proximal portionof the extension shaft 118.

After the cap 132 is engaged to the extension shaft 118, the surgeon canthen capture the alignment rod 140 with the slot 142 of the cap 132. Thecap 132 can then carry the alignment rod 140 down the length of theextension shaft 118 until the alignment rod 140 is captured and securedbetween the slot 142 of the cap 132 and the slot 108 of the head 106 ofthe pedicle screw 102.

The cap 132 is pushed down the length of the extension shaft 118 by thelocking nut 112. The locking nut 112 is threadedly engaged with theextension shaft 118 above the cap 132, such that as the surgeon drivesthe locking nut 112, the locking nut 112 pushes the cap 132 toward thehead 106 of the pedicle screw 102. The surgeon can then drive thelocking nut 112 until the cap 132 secures the alignment rod 140 to thehead 106.

Once fully secured, as shown in FIGS. 6-9 , the slot 142 of the cap 132and the slot 108 of the head 106 of the pedicle screw 102 will surroundthe circumference of the alignment rod, although not fully, enough toprevent the alignment rod 140 from breaking away from the pedicle screw102 in a lateral direction. In an embodiment, the cap 132 deforms aroundthe slot 142 as the nut 112 tightens the cap 132 against the head 106 ofthe pedicle screw 102. Due to the deformation of the cap 132, the cap132 cannot be used again after it has been fully secured to the head.

The cylindrical portion 110 of the head 106 has sufficient length toaccommodate both the cap 132 and the locking nut 112 when fully secured,such that, the extension shaft 118 can then be removed from engagementwith the pedicle screw 102.

As shown in FIGS. 13 and 14 , the extension shaft 118 can then bedisengaged from the pedicle screw 102 by unscrewing the inner rod 120from the threaded bore 128 within the head 106 of the pedicle screw 102,which will then release the extension shaft 118 from engagement with thepedicle screw 102.

Multiple spine alignment systems 100 can be secured to correspondingvertebra that a surgeon is attempting to set in alignment. Once all ofthe desired pedicle screws 102 are secured to the correspondingvertebra, caps 132 capturing the alignment rod 140 can be incrementallytranslated down their corresponding extension shafts 118 until thealignment rod 140 is secured to each of the heads 106 of the pediclescrews 102.

This incremental translation of the caps 132 and alignment rod 140 canprovide load sharing across the entire series of pedicle screws 102,decreasing the stress at individual bone-screw interfaces. Additionally,the incremental securement of the alignment rod 140 to the pediclescrews 102 can serve as a reduction tool, bringing all of the desiredvertebrae into alignment with the alignment rod 140, thereby reducingthe number of tools and steps during a surgical procedure.

Another advantage of the spine alignment system is that a surgeon candrive the pedicle screw 102 and the locking nut 112 with a powereddriving instrument, thus removing the need for manual and oftenlaborious tightening and alignment of the alignment rod 140 to thecorresponding pedicle screws 102. It will be appreciated that the use ofa powered driving instrument, whatever the source of the power, cangreatly improve the efficiency of the surgical procedure and thusbeneficially reduce the time required to complete the procedure.

FIGS. 15-26 illustrate another embodiment of a spine alignment system200 of the current disclosure. FIGS. 15-20 illustrate a pedicle screw202 and extension shaft 218 assembly of the spine alignment system 200.The spine alignment system 200 includes a poly-axial, pedicle screw 202.The pedicle screw 202 includes a threaded shaft which facilitatesinsertion and fixation into the bony pedicle of a vertebral body. Thethreaded shaft 204 may have a fixed or tapered diameter, with single ormultiple start threads which may be spaced from about 1 mm to about 3 mmapart, for example.

The pedicle screw 102 includes a head 206 having a generally sphericalshape. The head 206 is configured to receive a collet 207. The collet isalso configured to be received within the bottom, or distal end, of theextension shaft 218. The collet 207 includes an approximately C-shapedcut-out portion 208, or slot, located substantially on a side of thecollet 206. The slot 208 includes a longitudinal axis that issubstantially perpendicular to the longitudinal axis of the pediclescrew 202.

The collet 207 includes a conical-shaped receiving bore 209 that isconfigured to receive the head 206 of the pedicle screw 202. The collet207 includes a cylindrical portion 210 above, or proximal to, thereceiving bore 209. The cylindrical portion 210 includes the slot 208 ina side portion thereof.

The spine alignment system 200 also includes a spindle 212 that includesa threaded distal end 214 and a proximal head 216. As shown in FIG. 16 ,the collet 207 includes an interior threaded surface 220 within thecylindrical portion 210. The interior threaded surface 220 is configuredto threadedly engage with the threaded distal end 214 of the spindle212.

During use and assembly, the pedicle screw 202 can be inserted andsecured to the bony pedicle of a desired vertebrae. Then the collet 207can be placed over the head 206 of the pedicle screw 202. The collet 207can then be inserted into the distal end of the extension shaft 218. Thespindle 212 can then be inserted into the proximal end of the extensionshaft 118 until the spindle 212 is threadedly engaged with the collet207.

As shown in FIG. 17 , the spindle 212 can rest against an interiorflange 222 of the extension shaft 218 such that as the spindle 212drives into the collet 207, the collet 207 is pulled further and furtherinto the extension shaft 218 until the cylindrical portion 210 of thecollet 207 abuts the interior flange 222, opposite to the spindle 212.The head 216 of the spindle 212 is configured to receive and be drivenby a power or manual driver.

As the collet 207 is pulled into the extension shaft 218, the receivingbore 209 is tightened by contact with the distal end of the extensionshaft 218. As the receiving bore 209 is tightened, the receiving bore209 is rigidly secured to the head 206 of the pedicle screw 202, suchthat the pedicle screw will not be able to translate or rotate withrespect to the collet 207.

The extension shaft 218 also includes a head 224 having a generallyconical shape. The head 206 includes an approximately C-shaped cut-outportion 226, or slot, located substantially on a side of the head 224.The slot 226 includes a longitudinal axis that is substantiallyperpendicular to the longitudinal axis of the pedicle screw 202. Theslot 226 is substantially coaxial with slot 208 of the collet 207 whenfully assembled. The conical shape of the head 224 transitions to acylindrical shape above the slot 226, resulting in a cylindrical portion228. The cylindrical portion 228 includes an exterior thread configuredto receive a locking nut 230.

The extension shaft 218 includes external threads that are formed tomatch the threads on the cylindrical portion 228 of the head 224 suchthat the locking nut 230 can threadedly engage the extension shaft 218and the cylindrical portion 228 of the head 224.

The extension shaft 118 can be integrated with the head 224 with afracture groove cut 223 between the extension shaft 218 and the head224, which can enable the extension shaft 218 to break-away from thehead 224 after installation of the spine alignment system 200.

As shown in FIGS. 21-25 , the extension shaft 218 is configured toreceive a cap 232. The cap 232 includes an approximately shaped oblongthrough hole 234, substantially similar as that provided in cap 132discussed above, which includes a substantially flat side surface 236that is configured to lie flat against a flat side surface 238 of theextension shaft 218. The extension shaft 218 includes a pair of opposingflat side surfaces 238, one of the pair of flat surfaces 238 faces thesame direction as the slot 226 of the head 224. These flat side surfaces238 serve as a guide for the cap 232 after capturing an alignment rod240 and translating down the length of the extension shaft 218. Thealignment rod 240 is captured by the cap 232 within an approximatelyC-shaped cutout 242, or slot, which is formed and dimensioned tosubstantially the same diameter as the alignment rod 240 so as tosecurely capture the alignment rod 240.

One of the pair of flat surfaces 238 engages the alignment rod 240,helping secure the alignment rod 240 in place during axial translationof the cap 232 and the opposing flat surface 238 can engage the flatsurface 236 within the cap 232, helping to prevent unwanted rotation ofthe cap 232 during axial translation down the extension shaft 218.

During assembly or use, a surgeon or user can place the cap 232 onto theproximal portion of the extension shaft 218. After the cap 232 isengaged to the extension shaft 218, the surgeon can then capture thealignment rod 240 with the slot 242 of the cap 232. The cap 232 can thencarry the alignment rod 240 down the length of the extension shaft 218until the alignment rod 240 is captured and secured between the slot 242of the cap 232 and the slot 226 of the head 224.

The cap 232 can be pushed down the length of the extension shaft 218 bythe locking nut 230. The locking nut 230 is threadedly engaged with theextension shaft 218 above the cap 232, such that as the surgeon drivesthe locking nut 230, the locking nut 230 pushes the cap 232 toward thehead 224. The surgeon can then drive the locking screw until the cap 232secures the alignment rod 240 to the head 224. Once fulled secured, theslot 242 of the cap 232 and the slot 226 of the head 224 will surroundthe circumference of the alignment rod 240, although not fully, enoughto prevent the alignment rod 240 from breaking away from the pediclescrew 202 in a lateral direction. The cylindrical portion 228 of thehead 224 has sufficient length to accommodate both the cap 232 and thelocking nut 230 when fully secured, such that, the extension shaft 218can then be removed or broken from engagement with the head 224, asshown in FIG. 26 .

In accordance with a beneficial methods in accordance with the presentdisclosure, multiple spine alignment systems 200 can be secured tocorresponding vertebra that a surgeon is attempting to set in alignment.Once all of the desired pedicle screws 202 are secured to thecorresponding vertebra and corresponding extension shafts 218 aresecured to the pedicle screws 202, caps 232 capturing the alignment rod240 can be incrementally translated down their corresponding extensionshafts 218 until the alignment rod 240 is secured to each of the heads224 and pedicle screws 202. This incremental translation of the caps 232and alignment rod 240 can provide load sharing across the entire seriesof pedicle screws 202, decreasing the stress at individual bone-screwinterfaces. Additionally, the incremental securement of the alignmentrod 240 to the pedicle screws 202 can serve as a reduction tool,bringing all of the desired vertebrae into alignment with the alignmentrod 240, thereby reducing the number of tools, steps and duration of asurgical procedure.

Another exemplary advantage of the spine alignment system 200 is that asurgeon can drive the pedicle screw 202, spindle 212, and the lockingnut 230 with a power driven instrument, thus removing the need formanual and often laborious tightening and alignment of the alignment rod240 to the corresponding pedicle screws 202.

In an alternative embodiment, as shown in FIG. 27 , an alignment rod 300can be contoured. The alignment rod 300 is not linear, having a firstend 302 and a second end 304, where the first end 302 and the second end304 are not co-linear. Instead, the alignment rod 300 is contoured,having at least one curvature 306. In alternative embodiments thealignment rod 306 may include any desired number of curvatures, havingvarying or identical dimensions.

Additionally, a longitudinal axis A of the first end 302 is not coaxialwith the longitudinal axis B of the second end 304. However, thelongitudinal axis A may be substantially parallel to the Longitudinalaxis B, as shown in FIG. 27 , or the longitudinal axis A may intersectwith the longitudinal axis B.

The curvature 306 can be of custom size and dimension depending on thespecific needs of the patient. For example, a surgeon can decide thatthe alignment of a spine should occur in multiple stages, thus utilizingthe contoured alignment rod 300 can be a beneficial intermediate steptoward straightening the alignment of a spine.

Each of the components of the spine alignment systems 100 and 200 can befabricated from titanium or a titanium alloy, cobalt chrome, orstainless steel or other materials known to those skilled in the art.

FIGS. 28-33 , illustrate how multiple spine alignment systems 100 can besecured to corresponding vertebra 402 of a spine 400 that a surgeon isattempting to align. Systems 100 are identified by references numeralsin only a representative number, however, it can be assumed that thesystems or other corresponding elements that are not specificallyidentified by a reference numeral, are identical or substantiallysimilar to the corresponding enumerated elements.

As shown in FIG. 29 , each of the pedicle screws 102 are first securedto corresponding vertebra 402. As shown in FIG. 30-31 , caps 132 can beused to capture and secure the alignment rod 140. As the alignment rod300 is aligned and brought into contact with the extension shafts 118 ofthe systems 100, the caps 132 can be incrementally translated down theircorresponding extension shafts 118 until the alignment rod 300 issecured to each of the heads 106 of the pedicle screws 102.

A surgeon or user can insert and secure the pedicle screws 102 (includedin system 100), with the adjoined extension shaft 118, to the bonypedicle of a desired vertebra 402. Once the pedicle screw 102 issecured, the surgeon can then place the cap 132 onto the proximalportion of the extension shaft 118.

After the cap 132 is engaged to the extension shaft 118, the surgeon oruser can then capture the alignment rod 140 with the slot 142 of the cap132, as discussed in more detail previously. The cap 132 can then carrythe alignment rod 300 down the length of the extension shaft 118 untilthe alignment rod 300 is captured and secured between the slot 142 ofthe cap 132 and the slot 108 of the head 106 of the pedicle screw 102,as discussed above.

The series of caps 132, included in systems 100 in FIGS. 28-33 , areincrementally translated down the length of the extension shafts 118 bycorresponding locking nuts 112. The locking nuts 112 are threadedlyengaged with the extension shafts 118 above the caps 132, such that asthe surgeon drives the locking nuts 112, the locking nuts 112 push thecap 132 toward the head 106 of the pedicle screw 102. The surgeon canthen drive the locking nuts 112 until the caps 132 secure the alignmentrod 300 to the heads 106 of the pedicle screws 102.

As shown in FIG. 33 , once the alignment rods 300 are fully secured, theextension shafts 118 can then be removed from engagement with thepedicle screw 102, as discussed in more detail above.

The incremental translation of the caps 132 and alignment rods 300 canprovide load sharing across the entire series of pedicle screws 102,decreasing the stress at individual bone-screw interfaces. Additionally,the incremental securement of the alignment rod 140 to the correspondingpedicle screws 102 can serve as a reduction tool, as shown in FIG. 28 ,bringing all of the desired vertebrae into alignment with the alignmentrod 300, thereby reducing the number of tools and steps during asurgical procedure. As also shown in FIG. 28 , two alignment rods 300can be used, substantially parallel to one another and also parallelwith the aligned spine 400, to provide sufficient support for thealigned spine 400 and reduce the stress on any specific vertebra 402 orside of the vertebra 402.

Another advantage of the spine alignment system is that a surgeon candrive the pedicle screw 102 and the locking nut 112 with a powereddriving instrument, thus removing the need for manual and oftenlaborious tightening and alignment of the alignment rod 140 to thecorresponding pedicle screws 102. It will be appreciated that the use ofa such a driver, whatever the source of the power, can greatly improvethe efficiency of the surgical procedure and thus beneficially reducethe time required to complete the procedure.

And yet another advantage of the disclosed spine alignment system occursduring use with patients that have a substantial amount of fat aroundthe area of the spine 400. Conventionally, when dealing with suchpatients it can be very difficult for a surgeon to access and manipulatethe components of a convention spine alignment system because of thedepth of the spine with respect to the exterior of the patient's back,requiring a deeper access cavity to be cut into the patient's back. Thedisclosed spine alignment system, however, provides that the extensionshafts 118 extend well above the spine 400 allowing the surgeon toreadily manipulate the vertebrae 402 and the alignment rod 300 in suchpatients which increases the ease and efficiency which a surgeon cansecure the spine alignment system in place with respect to the spine400.

It is to be understood that the above-described arrangements are onlyillustrative of the application of the principles of the presentdisclosure. Numerous modifications and alternative arrangements may bedevised by those skilled in the art without departing from the spiritand scope of the present disclosure are intended to cover suchmodifications and arrangements. Thus, while the present disclosure hasbeen shown in the drawings and described above with particularity anddetail, it will be apparent to those of ordinary skill in the art thatnumerous modifications, including, but not limited to, variations insize, materials, shape, form, function and manner of operation, assemblyand use may be made without departing from the principles and conceptsset forth herein.

What is claimed:
 1. A spine alignment system, comprising: a pediclescrew having a longitudinal axis, the pedicle screw having a screw head,wherein the screw head includes a slot having a longitudinal axis thatis substantially perpendicular to the longitudinal axis of the pediclescrew; an extension shaft secured to the pedicle screw, such that alongitudinal axis of the extension shaft is substantially coaxial withthe longitudinal axis of the pedicle screw; a cap having a through-holeconfigured to receive the extension shaft, the through-hole having alongitudinal axis, wherein the cap includes a slot having a longitudinalaxis that is substantially perpendicular to the longitudinal axis of thethrough-hole, and wherein the slot of the screw head and the slot of thecap, together, form a substantially cylindrical passage configured toreceive an alignment rod; and, a nut configured to receive the extensionshaft and facilitate movement of the cap along the extension shaft. 2.The system of claim 1, wherein the pedicle screw is mono-axial.
 3. Thesystem of claim 1, wherein the head of the pedicle screw includes anexterior thread that threadedly engages the nut, wherein the nut securesthe cap to the head of the pedicle screw.
 4. The system of claim 1,further comprising: an alignment rod, wherein the alignment rod isreceived by the substantially cylindrical passage formed by the pediclescrew head and the cap, such that the alignment rod is laterally fixedwithin the substantially cylindrical passage.
 5. The system of claim 1,wherein the extension shaft is generally cylindrical in shape andincludes at least one substantially flat exterior surface parallel withthe longitudinal axis of the extension shaft.
 6. The system of claim 1,wherein the cap includes a substantially planar surface within thethrough-hole.
 7. The system of claim 6, wherein the substantially planarsurface of the cap is located on an opposite side of the through-holefrom the slot of the cap.
 8. The system of claim 1, wherein the slot ofthe cap extends more than 180 degrees in circumference.
 9. The system ofclaim 4, wherein the alignment rod is substantially linear.
 10. Thesystem of claim 4, wherein the alignment rod is curved along alongitudinal axis.
 11. The system of claim 4, wherein the slot of thecap is configured to retain the alignment rod in a snap-fit engagement.12. A spine alignment system, comprising: a pedicle screw having alongitudinal axis, the pedicle screw having a screw head, wherein thescrew head includes a slot having a longitudinal axis that issubstantially perpendicular to the longitudinal axis of the pediclescrew; an extension shaft secured to the pedicle screw, such that alongitudinal axis of the extension shaft is substantially coaxial withthe longitudinal axis of the pedicle screw, wherein the extension shaftalso includes a head, wherein the head includes a slot having alongitudinal axis that is substantially perpendicular to thelongitudinal axis of the pedicle screw; a cap having a through-holeconfigured to receive the extension shaft, the through-hole having alongitudinal axis, wherein the cap includes a slot having a longitudinalaxis that is substantially perpendicular to the longitudinal axis of thethrough-hole, and wherein the slot of the head and the slot of the cap,together, form a substantially cylindrical passage configured to receivean alignment rod; and, a nut configured to receive the extension shaftand facilitate movement of the cap along the extension shaft.
 13. Thesystem of claim 12, wherein the extension shaft is generally cylindricalin shape and includes at least one substantially flat exterior surfaceparallel with the longitudinal axis of the extension shaft.
 14. Thesystem of claim 12, wherein the head of the extension shaft includes aexterior thread that threadedly engages the nut, wherein the nut securesthe cap to the head of the pedicle screw.
 15. The system of claim 12,wherein the pedicle screw is poly-axial.
 16. The system of claim 12,further comprising: an alignment rod, wherein the alignment rod isreceived by the substantially cylindrical passage formed by the pediclescrew head and the cap, such that the alignment rod is laterally fixedwithin the substantially cylindrical passage
 17. The system of claim 12,wherein the cap includes a substantially planar surface within thethrough-hole.
 18. The system of claim 17, wherein the substantiallyplanar surface of the cap is located on an opposite side of thethrough-hole from the slot of the cap.
 19. The system of claim 12,wherein the slot of the cap extends more than 180 degrees incircumference.
 20. The system of claim 16, wherein the alignment rod issubstantially linear.
 21. The system of claim 16, wherein the alignmentrod is curved along a longitudinal axis.
 22. The system of claim 16,wherein the slot of the cap is configured to retain the alignment rod ina snap-fit engagement.
 23. A method of assembling a spine alignmentsystem, comprising: securing a pedicle screw, having a head, to a bonypedicle of a vertebra; securing an extension shaft to a pedicle screw;engaging a cap about the extension shaft such that the cap can translateaxially over a length of the extension shaft, the cap having a slothaving a longitudinal axis that is substantially perpendicular to alongitudinal axis of the extension shaft when the cap is engaged withthe extension shaft; capturing an alignment rod with the slot of thecap; incrementally translating the cap and alignment rod axially downthe extension shaft; and, securing the alignment rod to the pediclescrew such that the alignment rod cannot be moved laterally with respectto the pedicle screw.
 24. The method of claim 23, further comprising:aligning a plurality of vertebra along the alignment rod as thealignment rod is incrementally translated down the extension shaft. 25.The method of claim 23, wherein the extension shaft is generallycylindrical in shape and includes at least one substantially flatexterior surface parallel with the longitudinal axis of the extensionshaft.
 26. The method of claim 23, wherein the head of the pedicle screwincludes an exterior thread that threadedly engages a nut, wherein thenut secures the cap to the head of the pedicle screw.
 27. The method ofclaim 23, wherein the pedicle screw is poly-axial.
 28. The method ofclaim 23, wherein the alignment rod is substantially linear.
 29. Themethod of claim 23, wherein the alignment rod is curved along alongitudinal axis.
 30. The method of claim 23, wherein the pedicle screwis mono-axial.
 31. A method of assembling a spine alignment system,comprising: securing a pedicle screw, having a head, to a bony pedicleof a vertebra; securing an extension shaft to a pedicle screw; engagingan alignment rod with the extension shaft such that the alignment rodcan translate over a length of the extension shaft, incrementallytranslating alignment rod axially down the extension shaft; and,securing the alignment rod to the pedicle screw such that the alignmentrod cannot be moved laterally with respect to the pedicle screw.
 32. Themethod of claim 31, further comprising: engaging a cap about theextension shaft such that the cap can translate axially over a length ofthe extension shaft, the cap having a slot having a longitudinal axisthat is substantially perpendicular to a longitudinal axis of theextension shaft when the cap is engaged with the extension shaft; andcapturing the alignment rod with the slot of the cap.
 33. The method ofclaim 32, further comprising: incrementally translating the cap and thealignment rod axially down the extension shaft;
 34. The method of claim31, further comprising: aligning a plurality of vertebra along thealignment rod as the alignment rod is incrementally translated down theextension shaft.
 35. The method of claim 31, wherein the extension shaftis generally cylindrical in shape and includes at least onesubstantially flat exterior surface parallel with the longitudinal axisof the extension shaft.
 36. The method of claim 32, wherein the head ofthe pedicle screw includes an exterior thread that threadedly engages anut, wherein the nut secures the cap to the head of the pedicle screw.37. A spine alignment system, comprising: a pedicle screw having alongitudinal axis, the pedicle screw having a screw head, wherein thescrew head includes a slot having a longitudinal axis that issubstantially perpendicular to the longitudinal axis of the pediclescrew; an extension shaft secured to the pedicle screw, such that alongitudinal axis of the extension shaft is substantially coaxial withthe longitudinal axis of the pedicle screw, wherein the extension shaftis detachable from the pedicle screw; and an alignment rod configured toengage with the extension shaft such that the alignment rod isconfigured to translate axially along the extension shaft.
 38. Thesystem of claim 37, wherein the extension shaft is generally cylindricalin shape and includes at least one substantially flat exterior surfaceparallel with the longitudinal axis of the extension shaft.
 39. Thesystem of claim 37, further comprising: a cap having a through-holeconfigured to receive the extension shaft, the through-hole having alongitudinal axis, wherein the cap includes a slot having a longitudinalaxis that is substantially perpendicular to the longitudinal axis of thethrough-hole, and wherein the slot of the screw head and the slot of thecap, together, form a substantially cylindrical passage configured toreceive the alignment rod.
 40. The system of claim 39, furthercomprising: a nut configured to receive the extension shaft andfacilitate movement of the cap along the extension shaft.
 41. The systemof claim 39, wherein the alignment rod is received by the substantiallycylindrical passage formed by the pedicle screw head and the cap, suchthat the alignment rod is laterally fixed within the substantiallycylindrical passage.
 42. The system of claim 37, wherein the extensionshaft is configured to receive a power driving instrument, to facilitatethe powered driving of the extension shaft and the pedicle screw. 43.The method of claim 31, wherein securing of the pedicle screw andextension shaft is performed by a power driving instrument.